Re: Is it possible to speed up addition of "not null"?

From: Florian Weimer <fweimer(at)bfk(dot)de>
To: depesz(at)depesz(dot)com
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Is it possible to speed up addition of "not null"?
Date: 2012-02-02 14:30:51
Message-ID: 82ehud2tpg.fsf@mid.bfk.de
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* hubert depesz lubaczewski:

> procedure would look like:
> 1. update pg_attribute set attnotnull = true where attrelid = 'my_table'::regclass and attname = 'not-null-column';
> 2. delete from my_table where not-null-column is null; -- this shouldn't
> do anything, as I know that there are no null values, but just in
> case
> 3. pg_reorg of the table.

You could install a trigger before step 1 which prevents INSERTs and
UPDATEs which would add even more rows violating the constraint.

I'm not sure if the DELETE will actually do anything, given that
pg_attribute says that the column cannot be NULL.

--
Florian Weimer <fweimer(at)bfk(dot)de>
BFK edv-consulting GmbH http://www.bfk.de/
Kriegsstraße 100 tel: +49-721-96201-1
D-76133 Karlsruhe fax: +49-721-96201-99

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